The cargo bay of a pickup truck is generally formed by its truck bed, sidewalls and tailgate. The truck bed generally supports the weight of the items, and the sidewalls and tailgate protect these items and keep them from falling out of the bay during transport. While the sidewalls are rigidly fixed, the tailgate moves between open and closed positions to gain access to the cargo bay and its truck bed. Tailgates are typically latched or locked shut during transport, and unlatched and swung open to load and unload items in the cargo bay. When closed, the tailgate defines the length of the truck bed and its cargo bay. Many mid size or short bed pickups have a bed length of about 76 inches. Full size pickups typically have a bed length of about 97 inches, but this length is reduced by about 20 inches when a tool box is secured toward the front of the cargo bay.
A source of frustration with pickup trucks is that some items are just a little too long to fit in the cargo bay and close the tailgate. For example, many motorcycles, dirt bikes and four wheel recreational vehicles have a length of about 80 inches. Although the tailgate can be left open to accommodate these longer items, this is not generally desired for several reasons. First, the tailgate can bounce around during transport and be damaged. Second, resting the vehicle on the tailgate can overload and break the tailgate, particularly when traveling on a bumpy road. Third, leaving the tailgate down inhibits the proper use of the rear bumper and poses a safety risk. Fourth, although items are often secured in the cargo bay by a rope, cord, chain or some other means, leaving the tailgate down increases the possibility of items falling out the rear end of the truck during transport. This is of particular concern when transporting a wheeled vehicle.
Another problem with conventional pick up trucks is getting heavy items in and out of the cargo bay. The truck bed is typically elevated more than a couple feet above the ground. Heavy objects have to be lifted onto the truck bed, or lowered down from the truck bed. This can be difficult or impossible for a single person when a heavy item is involved. Items can be dropped and damaged, and the person can be seriously injured. The weight of a heavy item can also overload and damage the tailgate. While the pickup trucks and their truck beds are generally designed to handle loads in excess of two or more tons, conventional tailgates are typically designed to support about 1,000 pounds. Heavy items are best placed directly on the truck bed. Heavy items can buckle the sheet metal or otherwise damage the tailgate. Heavy items should not generally be placed on or toward the outer end of the tailgate as this creates the most stress on the tailgate.
Although ramps are frequently used to help load and unload items in the cargo bay, conventional tailgates do not readily accommodate these ramps. Ramps are typically placed with one end resting on the ground and the other end resting on the outer end of the tailgate. As an object such as a motorcycle, dirt bike or four wheel recreational vehicle moves up the ramp, more and more of its weight is supported by the end of the tailgate. When the motorcycle reaches the top of the ramp, most of its weight is supported by the end of the tailgate. The load on the tailgate is increased when a person sits on the vehicle to steer it as it moves along the ramp. Noticeable shifting, bending or breakage of the ramp or tailgate can cause the vehicle to fall off the ramp or tailgate, which can damage the vehicle or injure people on or near the vehicle.
A problem with detachable ramps is providing both ease of use and safety. Given the fixed height of the bed of the pickup truck is typically 24 to 36 inches, the incline or slope of the ramp is basically a function of its length. Yet, longer ramps are typically heavier to lift and more likely to bow or bend when a vehicle moves across them. In certain situations, bowing can lead to a dangerous bouncing effect and slipping. Although longer, single-piece detachable ramps are desirable because they do not require assembly, they can also be more unwieldy. For example, wooden boards are popular for ramps because they are inexpensive to purchase and may be readily obtained as scrap material from a construction project. Although thicker boards typically provide better stiffness and safety during use, they are also typically heavier, more expensive and may not be available as scrap material.
Yet, short ramps can compromise safety. The shorter the ramp, the steeper the incline. The length of the ramp is typically limited by the length of the truck bed so that the ramp can be transported for use to various locations. As a result, detachable ramps typically have a relatively steep incline angle of 30°. Yet, an excessively steep ramp incline is not particularly desirable as it can be dangerous for a person riding a recreational vehicle such as a dirt bike up or down a pickup truck ramp. When driving down a steep ramp, the bike striking the ground at a steep angle and can throw the rider or cause him or her to lose control of the bike. When driving up a steep ramp, the force of the vehicle when it first engages the ramp can push or cause the ramp to slide in the direction of travel, or cause the ramp to slide laterally or the front wheel to turn so that the vehicle drives off the ramp. Such occurrences are dangerous as they can cause the vehicle or rider to fall awkwardly against the ramp, truck or ground, and result in damage to the truck or recreational vehicle or even injure the rider or other nearby person.
Designs for extending the cargo bay of a pickup truck are well known. Some even form a ramp for loading and unloading recreational vehicles in the cargo bay. Unfortunately, these designs suffer from a variety of drawbacks. A first type of extension and ramp design is shown in U.S. Pat. No. 4,596,417 to Bennett, the disclosure of which is incorporated by reference. The device is mounted around the perimeter of a tailgate when the tailgate is in its lowered position. The extension device is removed and reattached to the outer end of the tailgate as a ramp. This type of extension is time consuming to use because it must be continuously attached, removed and reattached. Parts can also jam, fasteners can strip, and the proper tools have to be readily available. The device can also lead to overloading and damage to the tailgate for the above noted reasons.
A second type of extension and ramp design replaces the original tailgate of the pickup truck. An example of this type of design is shown in U.S. Pat. No. 6,834,903 to Harper, the disclosure of which is incorporated by reference. This device includes dual telescoping ramp assemblies that attach to the rear of the sidewalls of the pickup. When fully retracted and in its upright, closed and latched position, the device is similar to a conventional tailgate in that it does not extend the cargo bay. The device extends the cargo bay by swinging a first portion down into a horizontal position planar to the truck bed. The subsequent telescoping sections are rotated to a vertical position to form a partial barrier for retaining wheeled vehicles in the cargo bay. The ramps are formed by fully extending the telescoping ramp portions and rotating them to extend toward the ground.
There are several problems with this telescoping design. The design only forms a partial barrier for retaining wheeled vehicles in the cargo bay. Large openings remain between the sidewalls of the truck and the vertical ramp portions that form the partial barrier. Only the support lines supporting the tailgate extension obstruct these large openings. Items are free to engage and possibly cut or damage the tension lines, or fall out of the cargo through the large openings. Another problem is that the many telescoping sections can be bent and jam given the rugged environment of a pickup truck cargo bay and the fact that the device is exposed to the weather. A further problem is the heavy weight and significant cost of providing dual telescoping ramps to form a tailgate. Five telescoping sections are needed to produce a ramp incline angle close to 20°. Finally, the unsightly appearance of this design, particularly regarding the telescoping ramps, dissuades or precludes the owner from leaving this contraption in place when not in use. The original tailgate has to be reattached to return the pickup truck to its desired appearance.
The present invention is intended to solve these and other problems.